Precollege science education, particularly middle school where students first encounter courses dedicated to the sciences, has lacked the attention of the scientific and education communities. As a result, many middle level teachers are marginally prepared to teach contemporary science, the development of effective curricular materials has lagged, and schools devote inadequate resources and support to science. In the prior Phase I grant, experiment modules have been designed by scientists that address the core content of middle school Life Science. They utilize live (aquatic) organisms in the class room to stimulate inquiry into the properties of living organisms and make connections with related environmental health problems to link student learning with the world around them. Human environmental health was chosen as the biomedical context because it strongly relates to the macroscopic world in which middle school students live and provides age-appropriate learning opportunities for students as they begin to understand organisms and their underlying structures and mechanisms. During Phase II our specific objectives are 1. To infuse middle school Life Science education with attractive experiment modules that stress student inquiry. 2. To mount a comprehensive dissemination program with school systems that work with large numbers of minorities and students from families with lower socioeconomic status. 3. To utilize a 'train the trainer' method for lead teachers to achieve wide dissemination of the modules that involves close collaboration between scientists and educators and the lead teachers. 4. To provide teachers with full support to implement and sustain the modules through a science resource center. 5. To continue the development of the content of the modules. 6. To obtain a thorough formative and summative evaluation of the effectiveness of the curriculum modules and the entire mechanism for their delivery. 7. To establish a robust program to sustain the module dissemination to teachers after the completion of the grant.